ENT (Otorhinolaryngology) · MU Sofia

28. Clinical anatomy of the oral cavity.

Covers the clinical anatomy of the oral cavity, starting with its division into the oral vestibule and the oral cavity proper, then the boundaries. It goes through the lips, cheeks, palate, floor of the mouth and tongue, each with its nerves and blood supply. It ends with the oropharyngeal isthmus and a lymphatic drainage table, and adds clinical notes on carcinoma, cysts, salivary stones and Ludwig's angina.

Inside: 1 section · 7 labelled pictures · 1 table · 16 flashcards · 6 min

Topic 28 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 1 section, about 915 words (6 min of reading), with 16 flashcards.

In this note

  1. Clinical Anatomy of the Oral Cavity

Clinical Anatomy of the Oral Cavity

The oral cavity, or mouth, is the beginning of the digestive tract and is divided into two main parts by the dental arches: the Oral Vestibule and the Oral Cavity Proper. Its posterior limit is the Oropharyngeal Isthmus (the space between the palatoglossal arches).

Boundaries (general)

  • Anterior: Lips
  • Lateral: Cheeks
  • Superior: Hard + soft palate
  • Inferior: Floor of mouth
  • Posterior: Isthmus of fauces (opens to oropharynx)

I. Oral Vestibule: Space between lips/cheeks and teeth/gingiva.

A. Lips (Labia)

  • Structure: Composed primarily of the Orbicularis Oris muscle (innervated by Facial Nerve) which acts as a sphincter.
  • Zones:
  • External Skin: Contains hair follicles and sebaceous glands.
  • Vermilion Zone: The red portion, characterized by a thin, non-keratinized epithelium overlying a rich capillary bed, giving it its color. It lacks hair and sweat glands.
  • Internal Mucosa: Non-keratinized stratified squamous epithelium.
  • Innervation (Sensory): Upper Lip: Infraorbital nerve, Lower Lip: Mental nerve
  • Blood supply: Superior & inferior labial arteries (from facial a.)
  • Clinical Relevance: The lip is a common site for squamous cell carcinoma (SCC), and the vermilion border is a critical landmark for surgical excision and reconstruction.

B. Cheeks (Buccal Mucosa)

  • Structure: Formed by the Buccinator muscle (innervated by CN VII), lined internally by buccal mucosa.
  • Key Landmark: The Parotid Papilla (or Stensen's papilla) is a small elevation opposite the upper second molar tooth where the Parotid Duct (Stensen's duct) opens.
  • Innervation (Sensory): Buccal nerve (branch of CN V3).
  • Lymphatic Drainage: Submandibular and Preauricular lymph nodes.

II. Oral Cavity Proper: the tongue, hard and soft palate, and floor of the mouth.

A. Roof of the Mouth (Palate)

  1. 1. Hard Palate (Anterior 2/3):
  • Structure: Formed by the palatine process of the maxilla anteriorly and the horizontal plates of the palatine bones posteriorly. It separates the oral and nasal cavities. Covered by keratinized stratified squamous epithelium.
  • Innervation (Sensory): Greater palatine and Nasopalatine nerves (branches of CN V2).
  • Drainage: Primarily to the Deep Cervical and Retropharyngeal lymph nodes.
  1. 2. Soft Palate (Velum Palati) (Posterior 1/3):
  • Structure: A movable fold of mucous membrane and muscle attached to the posterior edge of the hard palate. Its free posterior margin has the Uvula in the midline. Elevates during swallowing and speech.
  • Muscles (Cranial Nerves):
  • Tensor Veli Palatini: Tenses the soft palate, opens the Eustachian tube (CN V3).
  • Levator Veli Palatini: Elevates the soft palate (Pharyngeal Plexus, CN X).
  • Palatoglossus: Depresses the soft palate and elevates the tongue (Pharyngeal Plexus, CN X).

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